Bassi, Jacopo. 2020. “On $C^*$-Algebras Associated to Actions of Discrete Subgroups of $\operatorname{SL}(2,\mathbb{R})$ on the Punctured Plane”. MATHEMATICA SCANDINAVICA 126 (3), 540-58. https://doi.org/10.7146/math.scand.a-120288.